Dynamic mathematical model,which is based on the character of power-plant boiler system,is established by the means of modularization. On the basis of dynamic mathematical models,simulation model of the object is created with the advanced continuous simulation language(ACSL).The validity of this model has been verified by the simulation experiments and analysis.The simulation model helps to evaluate the influences that the dynamic process in steam/water's side brings to the boiler's operation and have some directive significance to design method of boiler and optimize run.